I just tried your code, but it did not work for me.
URL of my forum: http://viabox.pl/forum/forum-viatoll/
There’s another fix, but it’s not preferred if you ask me:
Put this in your CSS:
<br />
.bbPress #sidebar {<br />
display:none;<br />
}<br />
This hides the sidebar from view in the browser, the code will be loaded anyway though (that’s why I don’t prefer it).
Edit/update:
Oh and then you ofcourse need to make the left area wider too, I think it will be something like this according to your code:
.bbPress #left-area {
width: 875px; /* change that 875 to whatever width you want/need */
}
I just removed the sidebar tag from the forum-single.php file and upload it to my theme directory and it worked well.
That does work too, but when the forum-single.php gets upgraded and you want to stay up date with your theme files you’ll have to re-do the change(s).